cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A127208 Union of all n-step Lucas sequences, that is, all sequences s(1-n) = s(2-n) = ... = s(-1) = -1, s(0) = n and for k > 0, s(k) = s(k-1) + ... + s(k-n).

Original entry on oeis.org

1, 3, 4, 7, 11, 15, 18, 21, 26, 29, 31, 39, 47, 51, 57, 63, 71, 76, 99, 113, 120, 123, 127, 131, 191, 199, 223, 239, 241, 247, 255, 322, 367, 439, 443, 475, 493, 502, 511, 521, 708, 815, 843, 863, 943, 983, 1003, 1013, 1023, 1364, 1365, 1499, 1695, 1871, 1959
Offset: 1

Views

Author

T. D. Noe, Jan 09 2007

Keywords

Comments

Noe and Post conjectured that the only positive terms that are common to any two distinct n-step Lucas sequences are the Mersenne numbers (A001348) that begin each sequence and 7 and 11 (in 2- and 3-step) and 5071 (in 3- and 4-step). The intersection of this sequence with the union of all the n-step Fibonacci sequences (A124168) appears to consist of 4, 21, 29, the Mersenne numbers 2^n-1 for all n and the infinite set of Eulerian numbers in A127232.

Crossrefs

Cf. A227885.

Programs

  • Mathematica
    LucasSequence[n_,kMax_] := Module[{a,s,lst={}}, a=Join[Table[ -1,{n-1}],{n}]; While[s=Plus@@a; a=RotateLeft[a]; a[[n]]=s; s<=kMax, AppendTo[lst,s]]; lst]; nn=10; t={}; Do[t=Union[t,LucasSequence[n,2^(nn+1)]], {n,2,nn}]; t

Formula

A247505 Generalized Lucas numbers: square array A(n,k) read by antidiagonals, A(n,k)=(-1)^(k+1)*k*[x^k](-log((1+sum_{j=1..n}(-1)^(j+1)*x^j)^(-1))), (n>=0, k>=0).

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 3, 1, 0, 0, 1, 3, 4, 1, 0, 0, 1, 3, 7, 7, 1, 0, 0, 1, 3, 7, 11, 11, 1, 0, 0, 1, 3, 7, 15, 21, 18, 1, 0, 0, 1, 3, 7, 15, 26, 39, 29, 1, 0, 0, 1, 3, 7, 15, 31, 51, 71, 47, 1, 0, 0, 1, 3, 7, 15, 31, 57, 99, 131, 76, 1, 0
Offset: 0

Views

Author

Peter Luschny, Nov 02 2014

Keywords

Examples

			n\k[0][1][2][3] [4] [5] [6]  [7]  [8]  [9]  [10]  [11]  [12]
[0] 0, 0, 0, 0,  0,  0,  0,   0,   0,   0,    0,    0,    0
[1] 0, 1, 1, 1,  1,  1,  1,   1,   1,   1,    1,    1,    1
[2] 0, 1, 3, 4,  7, 11, 18,  29,  47,  76,  123,  199,  322 [A000032]
[3] 0, 1, 3, 7, 11, 21, 39,  71, 131, 241,  443,  815, 1499 [A001644]
[4] 0, 1, 3, 7, 15, 26, 51,  99, 191, 367,  708, 1365, 2631 [A073817]
[5] 0, 1, 3, 7, 15, 31, 57, 113, 223, 439,  863, 1695, 3333 [A074048]
[6] 0, 1, 3, 7, 15, 31, 63, 120, 239, 475,  943, 1871, 3711 [A074584]
[7] 0, 1, 3, 7, 15, 31, 63, 127, 247, 493,  983, 1959, 3903 [A104621]
[8] 0, 1, 3, 7, 15, 31, 63, 127, 255, 502, 1003, 2003, 3999 [A105754]
[.] .  .  .  .   .   .   .    .    .    .     .     .     .
oo] 0, 1, 3, 7, 15, 31, 63, 127, 255, 511, 1023, 2047, 4095 [A000225]
'
As a triangular array, starts:
0,
0, 0,
0, 1, 0,
0, 1, 1, 0,
0, 1, 3, 1, 0,
0, 1, 3, 4, 1, 0,
0, 1, 3, 7, 7, 1,  0,
0, 1, 3, 7, 11, 11, 1, 0,
0, 1, 3, 7, 15, 21, 18, 1, 0,
0, 1, 3, 7, 15, 26, 39, 29, 1, 0,
		

Crossrefs

Programs

  • Maple
    A := proc(n, k) f := -log((1+add((-1)^(j+1)*x^j, j=1..n))^(-1));
    (-1)^(k+1)*k*coeff(series(f,x,k+2),x,k) end:
    seq(print(seq(A(n,k), k=0..12)), n=0..8);
  • Mathematica
    A[n_, k_] := Module[{f, x}, f = -Log[(1+Sum[(-1)^(j+1) x^j, {j, 1, n}] )^(-1)]; (-1)^(k+1) k SeriesCoefficient[f, {x, 0, k}]];
    Table[A[n-k, k], {n, 0, 12}, {k, 0, n}] (* Jean-François Alcover, Jun 28 2019, from Maple *)

A251706 6-step Fibonacci sequence starting with (0,0,0,0,1,0).

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 1, 2, 4, 8, 16, 31, 62, 123, 244, 484, 960, 1904, 3777, 7492, 14861, 29478, 58472, 115984, 230064, 456351, 905210, 1795559, 3561640, 7064808, 14013632, 27797200, 55138049, 109370888, 216946217, 430330794, 853596780, 1693179928, 3358562656
Offset: 0

Views

Author

Arie Bos, Dec 07 2014

Keywords

Comments

a(n+6) equals the number of n-length binary words avoiding runs of zeros of lengths 6i+5, (i=0,1,2,...). - Milan Janjic, Feb 26 2015

Crossrefs

Other 6-step Fibonacci sequences are A001592, A074584, A251707, A251708, A251709.

Programs

  • Mathematica
    LinearRecurrence[Table[1, {6}], {0, 0, 0, 0, 1, 0}, 40] (* Michael De Vlieger, Dec 09 2014 *)

Formula

a(n+6) = a(n) + a(n+1) + a(n+2) + a(n+3) + a(n+4) + a(n+5).
G.f.: x^4*(x-1)/(-1+x+x^2+x^3+x^4+x^5+x^6) . - R. J. Mathar, Mar 28 2025
a(n) = A001592(n+1)-A001592(n). - R. J. Mathar, Mar 28 2025

A251709 6-step Fibonacci sequence starting with (0,1,0,0,0,0).

Original entry on oeis.org

0, 1, 0, 0, 0, 0, 1, 2, 3, 6, 12, 24, 48, 95, 188, 373, 740, 1468, 2912, 5776, 11457, 22726, 45079, 89418, 177368, 351824, 697872, 1384287, 2745848, 5446617, 10803816, 21430264, 42508704, 84319536, 167254785, 331763722, 658080827, 1305357838, 2589285412
Offset: 0

Views

Author

Arie Bos, Dec 07 2014

Keywords

Crossrefs

Other 6-step Fibonacci sequences are A001592, A074584, A251706, A251707, A251708.

Programs

  • Mathematica
    LinearRecurrence[Table[1, {6}], {0, 1, 0, 0, 0, 0}, 40] (* Michael De Vlieger, Dec 09 2014 *)

Formula

a(n+6) = a(n) + a(n+1) + a(n+2) + a(n+3) + a(n+4) + a(n+5).
G.f.: x*(-1+x+x^2+x^3+x^4)/(-1+x+x^2+x^3+x^4+x^5+x^6) . - R. J. Mathar, Feb 27 2023

A125129 Partial sums of diagonals of array of k-step Lucas numbers as in A125127, read by antidiagonals.

Original entry on oeis.org

1, 1, 4, 1, 8, 11, 1, 12, 19, 26, 1, 19, 33, 45, 57, 1, 30, 58, 84, 102, 120, 1, 48, 101, 157, 197, 222, 247, 1, 77, 179, 292, 380, 436, 469, 502, 1, 124, 318, 546, 731, 855, 929, 971, 1013, 1, 200, 567, 1026, 1409, 1674, 1838, 1932, 1984, 2036
Offset: 1

Views

Author

Jonathan Vos Post, Nov 23 2006

Keywords

Comments

Array of partial sums of diagonals of L(k,n) begins: 0.|.1...4..11...26...57..120..247..502.1013.2036.
1.|.1...8..19...45..102..222..469..971.1984.
2.|.1..12..33...84..197..436..929.1932.
3.|.1..19..58..157..380..855.1838.
4.|.1..30.101..292..731.1674.
5.|.1..48.179..546.1409.
6.|.1..77.318.1026.
7.|.1.124.567.
8.|.1.200.
9.|.1.

Examples

			Row 1 of the derived array is the partial sum of the diagonal above the main diagonal of array of k-step Lucas numbers as in A125127, hence the partial sums of: 1, 7, 11, 26, 57, 120, 247, 502, 103, ... are 1 = 1; 8 = 1 + 7; 19 = 1 + 7 + 11; 45 = 1 + 7 + 11 + 26; and so forth.
		

Crossrefs

Formula

Row 0 = SUM[i=1..n]L(i,i) = A127128 = partial sum of main diagonal of array of A125127. Row 1 = SUM[i=1..n]L(i,i+1) = partial sum of diagonal above main diagonal of array of A125127. Row 2 = SUM[i=1..n]L(i,i+2) = partial sum of diagonal 2 above main diagonal of array of A125127. .. Row m = SUM[i=1..n]L(i,i+m) = partial sum of diagonal 2 above main diagonal of array of A125127.

A127232 Eulerian numbers A000295 appearing in the intersection of Fibonacci and Lucas sequences A124168 and A127208.

Original entry on oeis.org

1, 120, 524268, 140737488355280, 2596148429267413814265248164609936, 57896044618658097711785492504343953926634992332820282019728792003956564819712
Offset: 1

Views

Author

T. D. Noe, Jan 09 2007

Keywords

Comments

a(n) is common to the r-step Fibonacci sequence and the s-step Lucas sequence for s=A001792(n)-2 and r=s-n+1. See A127208 for more information about the intersection of Fibonacci and Lucas sequences.

Examples

			a(2)=120 appears in the 5-step Fibonacci sequence A001591 and the 6-step Lucas sequence A074584. a(3)=524268 appears in the 16-step Fibonacci sequence and the 18-step Lucas sequence.
		

Crossrefs

Programs

  • Magma
    [2^((n+2)*2^(n-1)-1)-(n+2)*2^(n-1): n in [1..7]]; // Vincenzo Librandi, Aug 26 2011
    
  • PARI
    a(n) = my(k=(n+2)*2^(n-1)); 2^(k-1)-k; \\ Michel Marcus, Mar 25 2016

Formula

a(n) = 2^(k-1)-k for k=A001792(n).

A227885 Primes in the union of all n-step Lucas sequences.

Original entry on oeis.org

2, 3, 7, 11, 29, 31, 47, 71, 113, 127, 131, 191, 199, 223, 239, 241, 367, 439, 443, 521, 863, 983, 1013, 1499, 1871, 2003, 2207, 3571, 6553, 8087, 8191, 9349, 16369, 32647, 32707, 36319, 63487, 65407, 65519, 122401, 126719, 131071, 196331, 260111, 524287
Offset: 1

Views

Author

Robert Price, Oct 25 2013

Keywords

Crossrefs

Programs

  • Mathematica
    plst={2}; plimit=10^39; For[n=2, n<=3+Log[2,plimit], n++, llst={}; For[i=1, i
    				

Formula

2 and the primes in A127208.
Previous Showing 11-17 of 17 results.